JP5713844B2 - Wireless communication apparatus and interference avoidance method - Google Patents

Description

  Embodiments described herein relate generally to a wireless communication apparatus that performs short-range wireless communication and an interference avoidance method.

  Currently, the wireless HD (WirelessHD) standard has been established as a wireless system technology for high-speed transmission using the millimeter wave band, and a conventional wireless local area network (especially 802.11a / b / g) As for standardization of such wireless system technology, progress is being made.

  Coexistence with other radio systems in the same frequency band has become a major issue for radio systems using the millimeter wave band.

  In general, for coexistence of different wireless systems in the same frequency band, a certain wireless system is replaced with another wireless system (for example, a system compliant with the wireless HD standard or a wireless LAN type system that is being standardized). And / or the interference received from the other wireless system (hereinafter referred to as “interfered”), and the detected interference / interfered Based on the situation, it is necessary to execute processing for coexisting with other wireless systems in the same frequency band (for example, processing for switching frequency channels).

  Conventionally, cognitive communication has been studied for grasping and coexisting interference with and interference with other wireless systems. For example, an estimation method of interference and determination of a channel to be used A method is considered. In this study, each wireless communication device in a wireless system receives a signal transmitted / received in another wireless system coexisting in the same frequency band, and uses the control information included in the received signal. A determination is made as to whether to change the frequency channel to be changed. For example, from the received power, antenna gain, amplifier gain information, etc., whether the transmission by the wireless communication device itself affects the wireless communication device of the other wireless system, or from the scheduling information of the other wireless system, the wireless Estimate whether there is a period during which the communication device itself can transmit and receive without affecting the wireless communication device of another wireless system, and if it is estimated that there is no effect or there is no period, it is determined to change the frequency channel Otherwise, it is determined not to change the frequency channel.

  However, this technique has a drawback in that it is essential to receive a signal transmitted / received in another wireless system or to decode the received signal to grasp the contents of the control information.

  On the other hand, in the conventional wireless LAN, access control by the CSMA / CA method is performed. According to this access control, each wireless communication device measures and detects the occupied state of the wireless channel before using the wireless channel, and randomly sets a backoff before transmission, so that a plurality of wireless communication devices are set. It is possible to use the bandwidth fairly between the two.

  On the other hand, as a method that emphasizes the simplification and efficiency of the connection, assuming a one-to-one connection, a random backoff is performed at the time of transmission of a control signal until the connection is established, and there is no backoff after the connection is established. A technique for performing transmission / reception at intervals (for example, SIFS, DIFS, etc. in an IEEE802.11 wireless LAN) has been considered.

  However, for example, if the frame transmission is performed at a shorter frame interval than the other for a certain period of time after the connection is established in order to speed up transmission / reception, interference / exposure between other wireless systems will occur. Depending on the relationship of interference, wireless communication devices of other wireless systems cannot transmit and receive. That is, when another wireless system is a wireless system in the form of a wireless LAN that detects the occupied state of the wireless channel before using the wireless channel, if frames with a short frame interval are continuously transmitted, The wireless communication device of the wireless system detects it as busy, and as a result, cannot transmit / receive during the continuous transmission period of those frames. For this reason, the problem that fairness is not maintained arises.

JP 2008-306665 A JP 2008-79045 A

  Conventionally, without receiving and decoding transmission / reception signals of other wireless systems coexisting in the same frequency band, estimating interference and interference, while maintaining fairness with other wireless systems based on the estimation results There has been no known technique that makes it possible to select a process necessary for coexistence.

  This embodiment estimates interference and interference without receiving and decoding transmission / reception signals of other wireless systems that coexist in the same frequency band, and based on the estimation results, achieves fairness with other wireless systems. An object of the present invention is to provide a radio communication apparatus and an interference avoidance method capable of selecting processing necessary for coexistence while maintaining.

  According to the embodiment, a wireless communication apparatus that uses a specific wireless communication method includes a transmission unit, a reception unit, an interference determination unit, and an interference control unit. The transmission unit uses a frequency channel selected from a plurality of frequency channels, uses a frequency channel that can interfere with the specific wireless communication scheme, and has a communication range wider than the specific wireless communication scheme. Frames are transmitted at a short frame interval or a long frame interval compared to a predetermined frame interval used in the wireless communication system. The receiving unit receives a frame using the selected frequency channel. The interference determination unit determines at least one of an error characteristic in the received frame and a busy state of the used frequency channel. The interference control unit controls whether to change the frequency channel, the length of the frame interval, or neither change based on at least one of the error characteristic and the busy situation .

The figure which shows the structural example of the radio | wireless communications system which concerns on 1st-17th embodiment. The figure for demonstrating the relationship (case A) of the interference between radio | wireless systems, and a to-be-interfered. The figure for demonstrating the relationship (case B) of the interference between radio | wireless systems, and a to-be-interfered. The figure for demonstrating the relationship (case C) of the interference between radio systems, and a to-be-interfered. The figure for demonstrating the relationship between the frame space | interval used at the time of the frame transmission / reception of a 1st radio | wireless system, and interference. The figure for demonstrating selection of the coexistence process based on the interference estimation in the 1st radio | wireless system which concerns on 1st Embodiment, and an estimation result. The flowchart which shows the process example in the 1st radio | wireless system which concerns on 1st Embodiment. 1 is a block diagram showing a configuration example of a wireless communication device in a first wireless system according to a first embodiment. The figure for demonstrating selection of the coexistence process based on the interference estimation and the estimation result in the 1st radio | wireless system which concerns on 2nd Embodiment. 9 is a flowchart illustrating a processing example in the first wireless system according to the second embodiment. The figure for demonstrating selection of the coexistence process based on the interference estimation in the 1st radio | wireless system which concerns on 3rd Embodiment, and an estimation result. 9 is a flowchart illustrating a processing example in the first wireless system according to the third embodiment. 10 is a flowchart illustrating a processing example in the first wireless system according to the fifth embodiment. The block diagram which shows the structural example of the radio | wireless communication apparatus in the 1st radio | wireless system which concerns on 10th Embodiment. A block diagram showing an example of composition of a radio communications apparatus in the 1st radio system concerning a 16th embodiment.

  Hereinafter, a wireless communication apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that, in the following embodiments, the same numbered portions are assumed to perform the same operation, and repeated description is omitted.

  Hereinafter, the wireless communication system of the present embodiment is referred to as a “first wireless system”. A configuration example of each wireless communication device included in the first wireless system will be described later.

  In the present embodiment, it is assumed that there may be one or more other wireless communication systems that may cause interference with the “first wireless system”. Hereinafter, such another wireless communication system is referred to as a “second wireless system”.

(First embodiment)
FIG. 1 shows an example of a wireless communication system of the present embodiment, that is, a first wireless system.

  As a specific example of the first wireless system, one using short-range wireless communication having a communication range of about several tens of cm at most is assumed. In the first wireless system, only wireless communication devices that fall within such a short communication range influence each other, so it is assumed that the number of wireless communication devices connected to one wireless communication device is at most several. In the example of FIG. 1, a state in which three wireless communication devices 1 to 3 are included in the first wireless system is illustrated. However, the number of wireless communication devices included in the first wireless system is not limited to three.

  As in the first embodiment, in a wireless communication system having a wide communication range of about several tens of centimeters, only a few wireless communication devices that fall within the communication range affect each other. Therefore, a technique in which importance is placed on interference avoidance and radio band fairness as in a conventional wireless LAN, for example, a single wireless communication apparatus transmits a broadcast signal (for example, a beacon signal) as an access point, and each wireless communication apparatus Rather than a method that performs random backoff control each time a message is transmitted, a method that emphasizes simplified and efficient connection is expected. As one of the techniques, when performing signal transmission, for example, a connection signal such as a connection request signal (Connect Request) for starting a connection is transmitted and received using, for example, random backoff control, and connected. As a first frame interval to be used after completion of the process of establishing a frame, a frame interval is initially set to a frame interval shorter than that of other wireless systems (for example, IEEE 802.11) when compared with a frame interval of a specific frame type. After that, frame interval adjustment (IFS adjustment) is performed. The second embodiment is similar to the above, but in the third embodiment, when compared with the frame interval of a specific frame type as the first frame interval to be used after the connection process is completed, another wireless system ( For example, the frame interval is initially set to a longer frame interval than IEEE 802.11), frame transmission is performed, and then frame interval adjustment (IFS adjustment) is performed. In the fourth embodiment, as the first frame interval to be used after the end of the connection process, whether to initially set a short frame interval or to initialize a long frame interval is selected each time.

  Next, interference and interference between the first radio system and the second radio system will be described with reference to FIGS.

  2 to 4, reference numerals 101 and 102 denote wireless terminal apparatuses included in the first wireless system, and reference numerals 103 and 104 denote communication ranges of the wireless terminal apparatuses 101 and 102, respectively. Reference numerals 121 and 122 denote wireless terminal apparatuses included in the second wireless system, and reference numerals 123 and 124 denote communication ranges of the wireless terminal apparatuses 121 and 122, respectively.

  Here, it is assumed that all or part of the frequency band used in the second radio system overlaps with all or part of the frequency band used in the first radio system. In the present embodiment, for example, a millimeter wave band is assumed as this frequency band.

  Further, the communication range of the wireless communication in the communication method used in the second wireless system is wider than the communication range of the wireless communication in the communication method used in the first wireless system (for example, a radius of 10 cm as described above). This means, for example, that the sum of the maximum transmission power and the antenna gain in the radio communication device of the second radio system is higher than that in the radio communication device in the first radio system. As a specific example of the communication range of the second wireless system, for example, a radius of m is assumed. Examples of the second wireless system include, but are not limited to, wireless HD, IEEE 802.11ad, WiGig, and the like.

  In the present embodiment, the number of types of different wireless systems that use the same frequency band is not limited to the two types illustrated in FIGS. For example, as another wireless system corresponding to the “second wireless system”, only one type of other wireless system may exist, or two or more types of other wireless systems may coexist. In any case, the configuration and operation of each wireless communication device in the “first wireless system” are basically the same. In the following, for the sake of simplification of description, as illustrated in FIGS. 2 to 4, a case where only one type of other wireless system corresponding to the “second wireless system” exists will be described as an example.

  2 to 4 exemplify a case where there are two wireless communication apparatuses for each wireless system, but the number is not limited to two. Further, the number of wireless communication devices that exist for each wireless system may be different.

  2 to 4 illustrate an environment in which the wireless communication devices 101 and 102 of the first wireless system and the wireless communication devices 121 and 122 of the second wireless system are mixed. 2 to 4 is a relative positional relationship between wireless systems (relative positional relationship between wireless communication devices belonging to different wireless systems), and the difference is the state of interference and interference. Appears as a difference.

  In the case shown in FIG. 2 (referred to as case A), the distance between the wireless terminal devices 101 and 102 of the first wireless system and the wireless terminal devices 121 and 122 of the second wireless system does not interfere or does not substantially interfere. Can happen if you are away. In this case A, there is no interference from the first radio system to the second radio system. In addition, regarding interference from the second wireless system to the first wireless system, there is no interference, or even if there is interference, it is only in a limited case that busy is detected (for example, transmission) (Only when receiving a beacon signal that is expected to be broadcast with high power and no beamforming). If beam forming is performed in the second radio system, this is a case where the beam does not overlap the first radio system. At this time, since the channel occupation rate of the beacon signal is low, even if the first wireless system cannot transmit and receive only while the beacon signal exists, the influence is small. Therefore, in case A, both the first radio system and the second radio system can coexist without special control.

  The case shown in FIG. 3 (referred to as case B) is a state in which there is no interference from the first radio system to the second radio system, but there is interference from the second radio system to the first radio system. There is a large difference in the sum of the maximum transmission power and the antenna gain between the first wireless system and the second wireless system (and the wireless terminal devices 101 and 102 of the first wireless system and the wireless terminal of the second wireless system) When the devices 121 and 122 are closer than the case A), it is considered that the situation as in the case B can occur. Alternatively, it is considered that the situation as in Case B may occur when the second wireless system performs beam forming.

  The case shown in FIG. 4 (referred to as case C) may occur when the wireless terminal devices 101 and 102 of the first wireless system and the wireless terminal devices 121 and 122 of the second wireless system are close to each other. In this case C, the first radio system and the second radio system detect each other's transmission / reception signals, which are interference. That is, both interference from the first radio system to the second radio system and interference from the second radio system to the first radio system occur.

  In addition to the three cases A to C, the distances between the wireless terminal devices 101 and 102 of the first wireless system and the wireless terminal devices 121 and 122 of the second wireless system are considerably different from each other, and are completely different from each other. Although there is a case (referred to as case D) that cannot interfere, case D is treated as being included in case A in this embodiment.

  Next, referring to FIG. 5, the relationship between the length of the frame interval (IFS: Interframe Space) of the first wireless system and the interference is shown as Case B (FIG. 3) in which there is interference between the wireless systems among the above three cases. ) And case C (FIG. 4) will be described.

  In FIG. 5, Data indicates data to be transmitted / received, A indicates Ack (Acknowledgement), and BA indicates Block Ack.

  In this embodiment, when compared with “frame interval of a specific frame type” as IFS, IFS shorter than other wireless systems (for example, wireless systems such as IEEE802.11) or longer than other wireless systems IFS (which may include IFS of the same degree as other wireless systems) is basically used.

  For example, in the first wireless system, it is assumed that the transmitting wireless communication device and the receiving wireless communication device use the short IFS or the long IFS during frame transmission / reception after the connection is established. Therefore, for example, whether the IFS is set to a short IFS as compared with the minimum frame interval of the frame intervals AIFS (Arbitration Interframe Space) used before frame transmission in other wireless systems such as IEEE 802.11. Or, it is assumed that whether to set a long IFS is changed.

  Using a short IFS in the first wireless system means that transmission / reception of the wireless communication device of the first wireless system can be (most) prioritized. On the other hand, using a long IFS in the first wireless system means that transmission / reception of the wireless communication device of the first wireless system can be (most) subordinated.

  As to whether to use a short IFS or a long IFS, for example, a method of setting a short IFS in advance as exemplified in the first and second embodiments, as exemplified in the third and fourth embodiments. A method of setting a long IFS in advance, a method of dynamically changing according to a predetermined standard as exemplified in the third embodiment, and the like can be considered.

  When there are a plurality of other wireless systems, for example, an IFS shorter than any other wireless system may be used as a short IFS, and any other wireless may be used as a long IFS. An IFS longer than the system may be used.

  In FIG. 5, (a) and (b) show the case where the first wireless system performs frame transmission with a short IFS (hereinafter also referred to as short IFS), and (c) and (d) Each of the cases where the first wireless system performs frame transmission using a long IFS (hereinafter also referred to as a long IFS) is shown. Moreover, (a) and (c) show the case of case B (FIG. 3), and (d) of (b) shows the case of case C (FIG. 4).

  In case B of FIGS. 5A and 5C, the transmission frame of the first wireless system does not interfere with the second wireless system, and therefore the second wireless system transmits and receives regardless of the first wireless system. . Therefore, regardless of whether the first radio system uses short IFS or long IFS, when transmission / reception of the second radio system is started, transmission / reception of the first radio system during Due to interference (one-sided), the received frame becomes a reception error.

  On the other hand, in case C of FIGS. 5B and 5D, the transmission frame of the first wireless system interferes with the second wireless system, so when the first wireless system starts transmission / reception, the second wireless system During transmission / reception of the frame, it detects that the channel is busy and stops transmission / reception.

  In FIG. 5B, since the first radio system has the short IFS setting, after the channel is cleared, the first radio system starts transmission of the next frame before the second radio system. Therefore, the second wireless system cannot substantially detect busy and start transmission / reception until the continuous transmission / reception of the first wireless system ends.

  On the other hand, in (d) of FIG. 5, since the 1st wireless system is long IFS setting, the probability that the 2nd wireless system can start transmission / reception becomes high after frame transmission / reception of a 1st wireless system.

  As described above, as a method of coexisting with the same frequency channel while maintaining fairness, it is conceivable to control the frame interval of the first radio system. Whether this method is effective as in the example of FIG. Has the problem of depending on the relationship with interference.

  Next, in consideration of these problems, the first wireless system has an interfering and interfering relationship between the current first wireless system and the second wireless system with each other wireless system. A signal from another wireless system (here, the second wireless system) is received as to whether the case A does not interfere (or almost does not interfere), the case B interferes unidirectionally, or the case C interferes with each other. Then, a mechanism for selecting a process for coexistence according to whether it is determined whether it falls under Case A, B, or C without decoding is shown.

  In the first embodiment, the first wireless system is based on the use of short IFS, and based on the characteristics of frame errors during frame transmission / reception by the short IFS, the case B or other cases (ie, the case) A or C), and further, whether the case A or C is determined based on the ease of frame transmission / reception after the IFS of the first wireless system is changed from the short IFS to the long IFS. Here, the ease of frame transmission / reception is, for example, a busy situation such as “busy detection rate indicating the probability of busy” or “busy occupation rate indicating the percentage of time that the channel is detected as busy”. Judgment.

  FIG. 6 shows an example of a list of selection of coexistence processing based on interference estimation and estimation results in the first embodiment. FIG. 7 shows an example of a flowchart of the process of selecting the coexistence process based on the interference estimation and the estimation result in the first embodiment.

  As described with reference to FIG. 5, when frame I / O is performed using short IFS, the second radio is transmitted in a situation where the transmission / reception of the first radio system interferes with the second radio system (see FIG. 5B). The system determines that the channel is busy based on the transmission / reception of the first radio system and does not transmit, and even after the channel is cleared, the first radio system starts the next frame transmission / reception with a short IFS. Therefore, the second wireless system waits for transmission. Therefore, not only in the case A (the case where they are not or substantially not interfere with each other) but also in the case C (the case where transmission / reception of the first radio system interferes with the second radio system) The frequency of occurrence of frame errors during frame transmission / reception by the short IFS of the first wireless system is considered to be low.

  On the other hand, in Case B, the second wireless system performs transmission / reception independently regardless of transmission / reception of the first wireless system. Therefore, transmission / reception of the first wireless system can be performed regardless of the frame interval of the first wireless system. An error due to interference of the second wireless system can occur, and therefore, the frequency of occurrence of frame errors during frame transmission / reception is considered to increase.

  Therefore, in the interference estimation and coexistence processing according to the first embodiment, first, using a frequency channel selected from a plurality of frequency channels, frame transmission / reception is performed by short IFS for a certain period of time. The characteristic is measured (step S11). As for the timing of the fixed period, for example, a timer T1 (not shown) may be set in step S11, and the fixed period may have elapsed with the timer timeout. In this way, by managing the measurement time using the timer, a more reliable measurement result such as an average value for a certain time can be obtained.

  Then, after the end of the fixed period (in the example of FIG. 7, after the timer time-out of the timer T1, the characteristics of frame transmission / reception errors within the fixed period are confirmed. For example, a case where an error occurs in N or more consecutive transmission frames is defined as a burst error (N is an integer greater than or equal to 2 defined in advance). Then, it is determined whether or not a burst error has occurred during the predetermined period, and the next processing is divided based on the determination result (step S12).

  Here, in the example shown in the first embodiment, a burst error occurs in case B (see FIGS. 5A and 6).

  Therefore, when it is determined in step S12 that a burst error has occurred, it is desirable to change the used frequency channel in order to avoid interference and coexist (step S14).

  On the other hand, if it is determined in step S12 that no burst error has occurred, in order to determine whether it is case A or case C, IFS adjustment is performed for a certain period, and frame transmission / reception is performed. Is performed (step S13). In the first embodiment, the short IFS set in the initial stage is changed to a long IFS.

  In case A where the interference does not interfere with each other or almost does not interfere, even if the IFS is changed to the long IFS, it is considered that the busy status such as the busy detection rate or the busy occupation rate does not change from before the IFS change.

  On the other hand, in the case C that causes mutual interference between the wireless systems, when the IFS of the first wireless system is set to the long IFS, that is, the second wireless system is compared with at least an IFS in a specific frame type. It is considered that the busy detection rate or busy occupancy rate in carrier sense before the start of transmission increases when IFS is set to be equal to or longer than that.

  Therefore, IFS is set to long IFS for a certain period, and it is determined whether Case A or Case C based on the ease of frame transmission / reception within the certain period, that is, the busy detection rate or busy occupancy rate.

  The busy detection rate or busy occupancy rate of frame transmission / reception by Long IFS is confirmed (step S15). If the busy detection rate or busy occupancy rate is high (eg, greater than or equal to a predefined threshold), case C Therefore, frame transmission / reception is continued with the long IFS set, and the process waits for the busy detection rate or busy occupation rate to decrease (steps S16 and S17). When the busy detection rate or busy occupancy rate is low in step S17 (for example, when the busy detection rate is less than the above threshold), IFS adjustment is performed so that efficient transmission / reception can be performed, that is, from long IFS. Returning to the initial short IFS, frame transmission / reception is performed (step S18).

  On the other hand, when the busy detection rate or the busy occupancy rate is low (for example, when the busy detection rate is less than the threshold value), it is considered to be case A, so that, as described above, the long IFS is returned to the short IFS, Frame transmission / reception is performed (step S18).

  Note that after the frequency channel is switched in step S14, for example, the processing of FIG. 7 may be executed again.

  Also in step S18, a timer may be activated, and when the timer times out, the necessity of IFS adjustment may be determined again, and IFS adjustment may be performed as necessary. The timer in this case may have the same length as the timer T1. Alternatively, it may be longer than the timer T1. When short IFS is selected, there is a high possibility that there are no interference sources around. Therefore, by increasing the time until the next interference estimation as in the latter case, interference estimation and coexistence determination are performed. It is possible to make it possible to coexist while reducing power consumption.

  Further, in addition to the busy status of frame transmission / reception by Long IFS (busy detection rate or busy occupancy rate, etc.), the busy status of frame transmission / reception by short IFS is also measured, and in step S15, the busy status of frame transmission / reception by short IFS is determined. If the busy state of frame transmission / reception by Long IFS becomes high (or if the degree of increase is equal to or greater than a predefined threshold), it is determined as case C, and the frame transmission / reception busy by short IFS is performed. If the busy state of frame transmission / reception by Long IFS does not change from the situation (or if the degree of increase is less than the threshold value), it may be determined as case A. The same applies to step S17. In this case, the busy status of frame transmission / reception by the short IFS may be measured, for example, at step S11 or between step S12 and step S13.

  Further, step S18 may be omitted from FIG. 7, and the process may proceed from step S15 or S17 to step S1 instead of step S18.

  Next, FIG. 8 schematically shows a block diagram for illustrating a configuration example of the wireless communication device 100 (wireless communication devices 1 to 3 in FIG. 1) in the first wireless system according to the present embodiment.

  As illustrated in FIG. 8, the wireless communication device 100 includes a wireless unit 20, a modem unit 30, a MAC processing unit 40, and an upper layer processing unit 50. The modem unit 30 includes a modulation unit 31 and a demodulation unit 32. The MAC processing unit includes a transmission unit 41, a reception unit 42, an interference control unit 43, and an interference determination unit 44. The radio unit 20, the modem unit 30, and the MAC processing unit 40 form a radio transmission / reception unit 60 as a whole. In the figure, reference numeral 10 denotes an antenna.

  First, an outline of an operation at the time of signal transmission of the wireless communication apparatus 100 will be described.

  The transmission unit 41 temporarily accumulates the frames output from the upper layer processing unit 50 in an internal transmission buffer, and performs processing such as adding a MAC header to the frames in the accumulation order. The frame is output to the modulation unit 31.

  The modulation unit 31 performs physical layer-related processing such as encoding processing, modulation processing, and addition of a physical header on the frame received from the transmission unit 41, and then outputs the frame to the radio unit 20.

  The radio unit 20 performs D / A conversion processing on the frame received from the modulation unit 31, performs frequency conversion to a frequency band for radio communication, and then transmits the frame via the antenna 10.

  In the above description, the transmission buffer has been described as existing inside the transmission unit 41, but instead, the transmission buffer may exist in a location other than the transmission unit 41 in the wireless transmission / reception unit 60, or other than the wireless transmission / reception unit 60. (For example, the upper layer processing unit 50), or any combination thereof.

  Next, an outline of an operation at the time of signal reception of the wireless communication apparatus 100 will be described.

  A signal received via the antenna 10 is given to the radio unit 20.

  The radio unit 20 performs frequency conversion to baseband and A / D conversion processing on the received signal, and then outputs the digitized signal to the demodulation unit 32.

  The demodulator 32 performs a process such as a demodulation process and a physical header analysis on the digitized signal, and outputs a demodulated frame to the MAC processor 40.

  The receiving unit 42 of the MAC processing unit 40 performs processing such as analysis of the MAC header on the demodulated frame, and when the received frame is a frame transmitted from the communication partner of the wireless communication device 100, The received frame is output to the layer processing unit 50.

  Here, in the wireless communication device 100 of the wireless system of the present embodiment that performs interference estimation and selection of coexistence processing based on the estimation result while performing transmission / reception at an IFS frame interval, interference determination is performed inside the MAC processing unit 40. Part 44 and interference control part 43. The interference determination unit 44 is connected to the interference control unit 43 and the reception unit 42. Further, the interference control unit 43 may be connected to the interference determination unit 44, the transmission unit 41, and the radio unit 20 related to channel switching, and may be connected to the modem unit 30 if necessary.

  First, the interference determination unit 44 instructs the reception unit 42 to “acquire error characteristics” / “check busy status” at appropriate timings. The interference determination unit 44 receives the “reception error occurrence report” from the reception unit 42, calculates “reception error characteristics” in a certain period, and notifies the interference control unit 43 after a certain period. Similarly, the interference determination unit 44 receives a “busy detection report” from the reception unit 42, calculates a busy situation such as “busy detection rate or busy occupancy rate” in a certain period, and after a certain period, the interference control unit 43 is notified.

  The interference control unit 43 determines whether the case A, the case B, or the case C is based on the determination result by the interference determination unit 44. Specifically, in the first embodiment, first, it is determined whether the case is B or case A / C based on the error characteristics, and then, whether the case is A or C based on the busy situation. Make a decision. Note that, as described in the second to fourth embodiments, other determination procedures may be used.

  When performing channel switching, the interference control unit 43 issues a channel switching instruction to the radio unit 20. When performing IFS adjustment, the transmitter 41 is notified of the IFS adjustment instruction or the changed IFS setting value.

  The interference determination unit 44 employs a configuration in which a function for managing the timer is provided inside the interference determination unit 44 in order to measure “error characteristics” / “busy status” for a certain period of time based on the timer. Also good. Instead, a configuration may be adopted in which a timer unit having a function of managing a timer is provided at any location in the wireless communication apparatus 100 of FIG. 8 and the interference determination unit 44 is connected to the timer unit. .

  As described above, according to the present embodiment, frame transmission / reception is performed in each wireless communication device of the first wireless system without receiving and decoding transmission / reception signals in other wireless systems coexisting in the same frequency band. Inferring interference and interference with other wireless systems using indicators such as the characteristics of errors in the network and the busy status of frequency channels, and the results of coexistence while maintaining fairness from the results ( Frequency channel change, IFS adjustment, etc.) can be selected.

(Second Embodiment)
The second embodiment will be described with a focus on differences from the first embodiment.

  The description made with reference to FIGS. 1 to 5 is basically applicable to the second embodiment. Further, the configuration example of the wireless communication apparatus of the first communication system according to the second embodiment is the same as the configuration example of FIG.

  In the first embodiment, an example is shown in which it is first determined whether the case is B or not based on the characteristics of the error, and then whether the case is A or C is determined under IFS adjustment. The second embodiment is the same as the first embodiment in that the first wireless system basically uses the short IFS. However, in the second embodiment, the short IFS causes transmission / reception for a certain period, the busy status such as busy detection rate or busy occupancy during transmission / reception or connection processing, and the characteristics of the frame error during frame transmission / reception. The determination of case A, B, or C is made using two indices.

  FIG. 9 shows an example of a list of coexistence processing selection based on interference estimation and estimation results in the second embodiment. FIG. 10 shows an example of a flowchart of the coexistence process selection process based on the interference estimation and the estimation result in the second embodiment.

  As described in the first embodiment, when frames are transmitted and received using the short IFS in the first wireless system, continuous frame transmission is compared with a frame interval of a specific frame type, for example, IEEE 802.11 or the like. Since the IFS is shorter than other wireless systems, the error characteristics after the start of transmission / reception of the first wireless system are the same in case A and case C.

  However, even when continuous frame transmission / reception is performed even during connection processing, carrier sense is performed at least during the first frame transmission. In case C where a plurality of wireless systems interfere with each other, the channel is busy during carrier sense. It is considered that the probability of being detected is higher than that in case A. Therefore, in the second embodiment, the busy detection rate or busy occupancy rate at the start of transmission or connection processing is used for the determination of case A or case C.

  In the interference estimation and coexistence processing according to the second embodiment, as in the first embodiment, first, using a frequency channel selected from a plurality of frequency channels, frame transmission / reception is performed using a short IFS for a certain period. The busy detection rate or busy occupancy during frame transmission / reception is measured (step S21).

  Next, the busy detection rate or busy occupancy rate is confirmed (step S22). If the busy detection rate or busy occupancy rate is low (eg, less than a predefined threshold), case A (ie, It is determined that the other radio system does not exist in the range that affects the first radio system, or the effect is assumed to be slight even if it exists, and the process returns to step S21 to return the frame by the short IFS Continue sending and receiving.

  On the other hand, when the busy detection rate or the busy occupancy rate is high (for example, when the busy detection rate is equal to or higher than the threshold value), the error rate characteristic is subsequently confirmed (step S23). If a burst error has occurred, it is determined that the situation is in Case B, and channel switching is instructed (step S25).

  If no burst error has occurred, it is determined that the situation is the case C, and it is determined that the transmission / reception of the first radio system is detected as busy by the carrier sense of the second radio system. Therefore, the transmission is changed to Long IFS for the sake of performance (step S24).

  Thereafter, the busy detection rate or busy occupancy rate during frame transmission / reception by long IFS is confirmed (step S26), and when it becomes low (for example, when it becomes less than the above threshold), transmission / reception is again performed by short IFS. Is performed (step S27).

  Note that after the frequency channel is switched in step S25, for example, the processing of FIG. 10 may be executed again.

  Also, in FIG. 10, after changing to long IFS in step S24, an example of continuing to use Long IFS until the busy detection rate or busy occupancy rate decreases is shown. After returning to the short IFS, the IFS adjustment may be performed at regular intervals until the busy detection rate or the busy occupation rate decreases.

  Further, step S27 may be omitted from FIG. 10, and the process may advance from step S26 to step S21 instead of step S27.

  As shown in FIG. 9, in the second embodiment, it is possible to determine case A, case B, or case C from the combination of the error characteristic and the busy situation. In FIG. 10, the determination is first performed in the busy state, and then the determination is performed based on the error characteristics. Instead, the order of steps S22 and S23 is reversed, and the determination is performed based on the error characteristics first. Next, a procedure for making a determination in a busy situation is possible, or steps S22 and S23 can be integrated to make a judgment based on the error characteristics and the busy situation.

  As described above, according to the present embodiment, transmission / reception of individual wireless communication devices of the first wireless system, such as error characteristics during frame transmission / reception and channel busy status (such as busy detection rate or busy occupancy rate). Using the two parameters obtained by the processing, the relationship with other wireless systems can be determined, and the processing necessary for coexistence can be selected.

(Third embodiment)
The third embodiment will be described with a focus on differences from the previous embodiments.

  The description made with reference to FIGS. 1 to 5 is basically applicable to the second embodiment. Further, the configuration example of the wireless communication apparatus of the first communication system according to the third embodiment is the same as the configuration example of FIG.

  In the first and second embodiments, in order to increase the speed and efficiency of the first wireless system, basically, after connection, the short IFS is selected to perform transmission / reception, and between the other wireless systems. In the case where there is a possibility of interference / interference, the process of changing the channel or changing to the long IFS is shown.

  By the way, in order to minimize the interference to other wireless systems, a method of grasping the situation can be considered as setting the first transmission / reception after connection to the Long IFS.

  In the third embodiment, an example will be described in which frame transmission / reception is started by Long IFS setting after connection.

  FIG. 11 shows an example of a list of coexistence processing selection based on interference estimation and estimation results in the third embodiment. Further, FIG. 12 shows an example of a flowchart of coexistence processing selection processing based on interference estimation and estimation results in the third embodiment.

  Similar to the second embodiment, the relationship with other wireless systems is determined based on two parameters such as error characteristics during frame transmission / reception and channel busy status (such as busy detection rate or busy occupancy rate). It is.

  In the interference estimation and coexistence processing according to the third embodiment, first, a frame channel transmission / reception is performed by Long IFS for a certain period using a frequency channel selected from a plurality of frequency channels, and a busy detection rate during frame transmission / reception is performed. Alternatively, the busy occupancy is measured (step S31).

  Next, the busy detection rate or busy occupancy rate is confirmed (step S32). If the busy detection rate or busy occupancy rate is low (eg, less than a predefined threshold), case A (ie, It is determined that the other radio system does not exist in the range that affects the first radio system, or the effect is assumed to be slight even if it exists, and IFS adjustment is performed for speeding up. Thereafter, frame transmission / reception is performed by the short IFS (step S33).

  On the other hand, when the busy detection rate and the busy occupancy rate are high (for example, when the busy detection rate is equal to or higher than the threshold value), the frame error rate characteristic is subsequently confirmed (step S34), and a burst error occurs. If so, it is determined that the situation is in case B, and channel switching is instructed (step S35).

  If no burst error has occurred, it is determined that the situation is the case C, and the long IFS is used in the same frequency channel (that is, nothing is done in this case).

  After that, the busy detection rate or busy occupancy rate during frame transmission / reception by long IFS is confirmed (step S36), and if it becomes low (for example, when it becomes less than the above threshold), transmission / reception is performed by short IFS. (Step S37), otherwise, return to Step S31.

  Note that after the frequency channel is switched in step S35, for example, the processing of FIG. 12 may be executed again.

  As shown in FIG. 11, in the second embodiment, it is possible to determine whether the case A, the case B, or the case C is based on the combination of the error characteristic and the busy situation. In FIG. 11, the determination is first performed in the busy situation, and then the determination is performed based on the error characteristics. Instead, the order of steps S32 and S34 is reversed, and the determination is performed based on the error characteristics first. Next, a procedure for making a determination in a busy situation is possible, or steps S32 and S34 can be integrated to make a judgment based on an error characteristic and a busy situation in a lump.

  In the example of FIG. 11, in case C, in order to suppress interference with other wireless systems, in a period in which there is interference, that is, a period in which the busy detection rate or busy occupancy rate is high. Long IFS was supposed to be used. On the other hand, even during periods when the busy detection rate and busy occupancy rate are high, it is possible to obtain some throughput of the own radio system while maintaining fairness with other radio systems by repeatedly using long IFS and short IFS using a timer. A mechanism may be used.

  As described above, according to the present embodiment, transmission / reception of individual wireless communication devices of the first wireless system, such as error characteristics during frame transmission / reception and channel busy status (such as busy detection rate or busy occupancy rate). By using the two parameters obtained by the processing, the relationship with other wireless systems is judged, and by using Long IFS as a basic frame interval, interference / coverage with other wireless systems can be determined. In the presence of interference, interference with other wireless systems can be suppressed.

(Fourth embodiment)
The fourth embodiment will be described with a focus on differences from the previous embodiments.

  In the first to third embodiments, the basic IFS transmission is set to the short IFS (first and second embodiments) and the long IFS is used for the interference estimation and the coexistence processing selection method based on the estimation result. Each case has been described for the case (third embodiment).

  In the fourth embodiment, basic IFS transmission after connection is dynamically set to either a short IFS or a long IFS. In the fourth embodiment, it is assumed that the connection request signal / connection response signal is used for the connection process, and whether the short IFS or the long IFS is set is determined based on the transmission ratio of the connection request signal during the connection process. To do.

  In this case, in the first wireless system, a certain wireless communication device transmits a connection request signal, and the wireless communication device that has received the connection request signal transmits a connection response signal to perform connection processing. Therefore, if the connection request signal transmission side detects that the channel is busy at the timing of trying to transmit the connection request signal, it waits for the channel to clear, performs backoff, and then transmits the signal. To do. When there is no interference, the channel is clear, so it is possible to transmit the connection request signal reliably at the timing of trying to transmit the connection request signal. it can. On the other hand, if the channel is busy at the timing of attempting transmission as described above, the number of transmission request signals that can be transmitted within a certain time is considered to decrease. Therefore, the ratio of the number of connection request signals that can actually be transmitted to the number of connection request signals that can be transmitted is used as the transmission ratio of the transmission request signal, and this transmission ratio is used as a parameter to determine the IFS setting after connection To do.

  FIG. 13 shows an example of a processing flowchart in the present embodiment.

  The connection process is executed as described above (step S41), and the IFS setting after connection is determined based on the transmission ratio (step S42). Note that the interference determination unit 44 determines the transmission ratio, and the interference control unit 43 may determine which of the short IFS and the long IFS is selected.

  When the transmission ratio is high (for example, when the transmission rate is equal to or higher than a predefined threshold), it is unlikely that another radio system is using the same frequency channel, and basically short IFS after connection is established. Is used (step S43). In this case, for example, the process of FIG. 7 of the first embodiment or the process of FIG. 10 of the second embodiment may be performed.

  On the other hand, when the transmission ratio is low (for example, when it is less than the above threshold), it is highly possible that another wireless system is using the same frequency channel, and long IFS is basically used after connection. (Step S44). In this case, for example, the process of FIG. 12 of the third embodiment may be performed.

  As described above, according to the present embodiment, when there is a high possibility that another wireless system exists, by starting transmission / reception in the Long IFS setting after connection, interference with the other wireless system is reduced. In the case where there is a low possibility that another wireless system is present while suppressing, highly efficient frame transmission / reception can be performed by starting transmission with the short IFS setting.

(Fifth embodiment)
The fifth embodiment will be described with a focus on differences from the previous embodiments.

  In the first to fourth embodiments, several different examples of interference estimation and the coexistence processing selection method based on the estimation result have been shown. However, Case B that interferes unidirectionally, that is, the signal from the first radio system does not affect the second radio system, and the signal of the second radio system is detected as channel busy for the first radio system. In any of the first to fourth embodiments, channel switching is instructed for the situation.

  By the way, in the millimeter wave band, in general, there may be a difference in analog reception characteristics or the like for each frequency channel. Therefore, if the frequency channel is changed, the obtained transmission rate or the like may be reduced. Therefore, even if there is interference with other wireless systems, it is not always best to change the frequency channel. It would be desirable to avoid using channels with poor characteristics as a result of immediate channel switching. Further, it is desirable to use a desired frequency channel (default channel) as much as possible.

  Therefore, in the fifth embodiment, when channel switching is designated by the selection method of the first to fourth embodiments, whether or not channel switching should be actually performed instead of immediately performing channel switching, or the same. An example of determining whether coexistence should be performed in the default channel is shown.

  The wireless communication device can estimate the transmission rate at the time of frame transmission on the default channel and the transmission rate on the switching channel from the characteristics for each frequency channel. Therefore, the channel clear rate indicating the transmission rate information and the frame transmission / reception possible period (here, “channel clear rate = 1−channel busy detection rate” is used as an example), for example, “by default frequency channel Is compared with “transmission rate in switching channel × channel clearing rate in switching channel” to determine whether to coexist in the default channel or to perform channel switching. For example, in order to efficiently perform the determination, for example, the “channel clear rate in the switching channel” may be regarded as a specific value. As a specific value, for example, 1 may be used (a channel clear rate = 1 in a switching channel means that all channels are free).

  By deciding whether it is better to change the channel from the empty rate of the channel and the transmission rate obtained from the characteristics of the channel, it is possible to easily change the channel and avoid using a channel with poor characteristics.

  As another method, it may be determined whether or not to perform channel switching according to whether or not the throughput requested by the application or the like is satisfied by “transmission rate in default frequency channel × channel clear rate”.

  It is also possible to devise a frame transmission / reception method in the case where it is determined that transmission / reception is performed while coexisting with other wireless systems on the same channel due to interference of other wireless systems. Here, for example, the case C, the case where it is determined that the channel switching is not performed in the case B described above, or the case where the corresponding channel is only one channel of the default channel corresponds to the above case.

  For example, when the second wireless system performs transmission / reception independently of the first wireless system as in case B, the frame to be transmitted is divided into a plurality of frames called fragments, and the frame length actually transmitted / received is shortened. (By reducing the size of one frame), the channel occupancy time of one frame is further shortened, thereby transmitting and receiving while avoiding interference or suppressing characteristic deterioration due to interference as much as possible. It is desirable to reduce errors during device transmission and reception. At this time, the ease of frame transmission before fragmentation may be used to determine whether or not to perform fragmentation.

  On the other hand, when the second wireless system detects the transmission / reception of the first wireless system as busy as in case C, the frame length to be transmitted is increased by aggregation or the like, and the transmission / reception is performed with high efficiency. It is desirable to release the channel as soon as possible, for example, by adjusting the transmission rate or not transmitting / receiving for a certain period of time.

  As described above, according to the present embodiment, by considering the difference in characteristics for each frequency channel and finally determining whether to perform channel switching, there is no interference due to easy channel switching. However, it is possible to suppress the occurrence of a situation where the required throughput cannot be obtained. For example, even if it is basically determined that a channel change is desirable, if there is a large difference in characteristics depending on the frequency channel, it is possible to choose not to switch the frequency channel but to coexist on the same frequency channel. Provides higher throughput.

  Below, the variation with respect to embodiment described so far is demonstrated. Any one of the following embodiments or any combination of the following embodiments can be implemented in combination with any of the embodiments described above.

(Sixth embodiment)
In the sixth embodiment, a configuration including a buffer will be described in addition to the configuration of the wireless communication device of the first wireless system of the previous embodiments (see, for example, the wireless communication device 100 in FIG. 8). The buffer is connected to each of the transmission unit 41 and the reception unit 42. The buffer may exist inside the upper layer processing unit 50, may exist between the transmission unit 41 / reception unit 42 and the upper layer processing unit 50, or may be a combination thereof. . Thus, by adopting a configuration in which the buffer is included in the wireless communication apparatus, transmission / reception data can be held in the buffer, and retransmission processing and / or external output processing can be easily performed.

(Seventh embodiment)
In the seventh embodiment, a configuration including a bus, a processor unit, and an external interface in addition to the configuration of the wireless communication apparatus of the sixth embodiment will be described. The bus is connected to the buffer shown in the sixth embodiment, and the processor unit and the external interface unit are each connected to the bus (that is, both the processor unit and the external interface unit are connected to the buffer via the bus). Firmware may operate in the processor unit. These processor units, buses, and external interfaces may exist in the upper layer processing unit 50, may exist independently of the upper layer processing unit 50, or may be a combination thereof. good. As described above, by configuring the firmware to be included in the wireless communication device, it is possible to easily change the function of the wireless communication device by rewriting the firmware.

(Eighth embodiment)
In the eighth embodiment, a configuration including a moving image compression / decompression unit in addition to the configuration of the wireless communication apparatus of the seventh embodiment will be described. The moving image compression / decompression unit is connected to the bus shown in the seventh embodiment. As described above, by providing the wireless communication device with the moving image compression / decompression unit, it is possible to easily transmit the compressed moving image and expand the received compressed moving image.

(Ninth embodiment)
In the ninth embodiment, a configuration including a clock generation unit will be described in addition to the configuration of the wireless communication device of the first wireless system of the previous embodiments. The clock generation unit is connected to a wireless transmission / reception unit (see the wireless transmission / reception unit 60 in FIG. 8) of the wireless communication device. The clock generated by the clock generation unit is output to the outside via the output terminal. As described above, the clock generated inside the wireless communication device is output to the outside, and the host side is operated by the clock output to the outside, so that the host side and the wireless communication device side are operated in synchronization. Is possible.

(Tenth embodiment)
In the tenth embodiment, a configuration including a power supply unit, a power supply control unit, and a wireless power supply unit will be described in addition to the configuration of the wireless communication device of the first wireless system of the previous embodiments. The power supply unit, the power supply control unit, and the wireless power supply unit are connected to a wireless transmission / reception unit of the wireless communication device. As an example, FIG. 14 shows a configuration example when a power supply unit, a power supply control unit, and a wireless power feeding unit are added to the wireless communication apparatus 100 of FIG. In the wireless communication apparatus 1100 illustrated in FIG. 14, the power supply unit 101, the power supply control unit 102, and the wireless power supply unit 103 are all connected to the wireless transmission / reception unit 60. As described above, by providing the wireless communication apparatus with the power supply, it is possible to perform a low power consumption operation by controlling the power supply.

(Eleventh embodiment)
In the eleventh embodiment, in addition to the configuration of the wireless communication apparatus of the tenth embodiment, a configuration including an NFC (Near Field Communications) transmission / reception unit is shown. The NFC transmission / reception unit is connected to the power supply control unit and the MAC processing unit of the wireless communication apparatus. For example, in the case of the wireless communication apparatus 1100 of FIG. 14, the NFC transmission / reception unit is connected to the power supply control unit 102 and the MAC processing unit 40 in the wireless transmission / reception unit 60 of FIG. The NFC transmission / reception unit may exist inside the upper layer processing unit (50) or may exist independently of the upper layer processing unit (50). As described above, the wireless communication device includes the NFC transmission / reception unit, so that authentication processing can be easily performed, and power control is performed using the NFC transmission / reception unit as a trigger, thereby reducing power consumption during standby. Electricity can be achieved.

(Twelfth embodiment)
In the twelfth embodiment, a configuration including a SIM card is shown in addition to the configuration of the wireless communication apparatus of the tenth or eleventh embodiment. The SIM card is connected to the MAC processing unit (40). The SIM card may exist inside the upper layer processing unit (50) or may exist independently of the upper layer processing unit (50). As described above, by adopting a configuration in which the SIM card is provided in the wireless communication device, authentication processing can be easily performed.

(13th Embodiment)
In the thirteenth embodiment, a configuration including an LED unit will be described in addition to the configuration of the wireless communication device of the first wireless system of the previous embodiments. The LED unit is connected to a wireless transmission / reception unit (see the wireless transmission / reception unit 60 in FIG. 8) of the wireless communication device. As described above, by providing the wireless communication device with the LED, it is possible to easily notify the user of the operation state of the wireless communication device.

(Fourteenth embodiment)
In the fourteenth embodiment, a configuration including a vibrator unit will be described in addition to the configuration of the wireless communication device of the first wireless system of the previous embodiments. The vibrator unit is connected to a wireless transmission / reception unit (see the wireless transmission / reception unit 60 in FIG. 8) of the wireless communication device. As described above, the configuration in which the vibrator is provided in the wireless communication device makes it possible to easily notify the user of the operation state of the wireless communication device.

(Fifteenth embodiment)
In the fifteenth embodiment, in addition to the configuration of the wireless communication apparatus of the first wireless system of the previous embodiments, the antenna 10 describes a wireless communication apparatus. By adopting a configuration in which the antenna 10 is included in the wireless communication device 1, the wireless communication device can be configured as one device including the antenna, and the mounting area can be reduced. For example, as shown in FIGS. 8 and 14, the antenna 10 is shared by the transmission process and the reception process. Thus, by sharing one antenna for transmission processing and reception processing, it is possible to reduce the size of the wireless communication device.

(Sixteenth embodiment)
In the sixteenth embodiment, a configuration including a wireless LAN unit and a wireless switching unit will be described in addition to the configuration of the wireless communication device of the first wireless system of the previous embodiments. As an example, FIG. 15 shows a configuration example when a wireless LAN unit and a wireless switching unit are added to the wireless communication device 100 of FIG. In the wireless communication apparatus 1200 illustrated in FIG. 14, the wireless LAN unit 161 is connected to the upper layer processing unit 50 and the wireless switching unit 162, and the wireless switching unit 162 includes the wireless transmission / reception unit 60, the upper layer processing unit 50, and the wireless switching unit 162. Connected to the LAN unit 161. As described above, by configuring the wireless communication device to have the wireless LAN function, it is possible to switch between wireless LAN communication and wireless transmission / reception unit 500 communication depending on the situation. In particular, as described above, a plurality of channels can be used in the millimeter wave band. For example, in the first wireless system, any channel has a large interference with other wireless systems, and a desired transmission / reception cannot be performed. May be switched to communication by wireless LAN. Here, the wireless LAN to be switched may be a wireless system (for example, IEEE 802.11a, b, g, etc.) that uses a frequency band different from that of the first wireless system, or uses the same frequency band as the first wireless system. A wireless system (for example, 802.11ad) may be used. Also, the wireless LAN unit may have its own transmission / reception antenna, and in the case of a wireless LAN using the same frequency band as the first wireless system, the antenna may be shared with the first wireless system.

(Seventeenth embodiment)
In the seventeenth embodiment, a configuration including a switch (SW) in addition to the configuration of the wireless communication apparatus of the sixteenth embodiment will be described. The switch is connected to the wireless transmission / reception unit, the wireless LAN unit, and the wireless switching unit. For example, in the case of the wireless communication apparatus 1200 of FIG. 15, the switch is connected to the wireless transmission / reception unit 60, the wireless LAN unit 161, and the wireless switching unit 162 of FIG. As described above, by configuring the switch in the wireless communication device, it is possible to switch between communication by the wireless LAN and communication by the wireless transmission / reception unit according to the situation while sharing the antenna.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  1 to 3, 100, 1100, 1200 ... wireless communication device, 10 ... antenna, 20 ... wireless unit, 30 ... modulator / demodulator, 31 ... modulator, 32 ... demodulator, 40 ... MAC processor, 41 ... transmitter, 42 DESCRIPTION OF SYMBOLS ... Reception part, 43 ... Interference control part, 44 ... Interference determination part, 50 ... Upper layer processing part, 60 ... Wireless transmission / reception part, 101 ... Power supply part, 102 ... Power supply control part, 103 ... Wireless power feeding part, 161 ... Wireless LAN unit, 162... Wireless switching unit.

Claims (17)

In a wireless communication device using a specific wireless communication method,
Using a frequency channel selected from a plurality of frequency channels, using a frequency channel capable of interfering with the specific wireless communication method, and having another communication range wider than the specific wireless communication method A transmission unit for transmitting a frame at a short frame interval or a long frame interval compared to a predetermined frame interval to be used;
A receiving unit for receiving a frame using the selected frequency channel;
An interference determination unit for determining at least one of an error characteristic in the received frame and a busy status of the frequency channel being used;
An interference control unit for controlling whether to change the frequency channel, to change the length of the frame interval, or not to change based on at least one of the error characteristic and the busy situation; Including wireless communication device. The interference determination unit determines the error characteristic,
The wireless communication apparatus according to claim 1, wherein the interference control unit selects to change the frequency channel when the error characteristic reaches a reference. The short frame interval is initially set as the frame interval to be used,
The wireless communication according to claim 2, wherein the interference control unit selects to change the frame interval to be used to the long frame interval once when the error characteristic does not reach a reference. apparatus. The interference determination unit determines and uses a busy condition under the short frame interval of the frequency channel being used before the frame interval to be used is changed to the long frame interval. If the frame interval is changed to the long frame interval, further determine the busy status of the frequency channel being used under the long frame interval;
When there is no change between the busy status under the short frame interval and the busy status under the long frame interval, the interference control unit returns the frame interval to be used to the short frame interval. The wireless communication device according to claim 3, wherein the wireless communication device is selected. The short frame interval is initially set as the frame interval to be used,
The interference determination unit determines the error characteristic and the busy situation under the short frame interval,
The interference control unit selects to change the frequency channel when the error characteristic reaches a reference, and when the busy situation does not reach the reference, the interference control unit shortens the frame interval to be used. 2. The wireless communication apparatus according to claim 1, wherein it is selected to maintain the frame interval, and in other cases, it is selected to change the frame interval to be used to the long frame interval.   The interference control unit first checks the busy situation, and if the busy situation does not reach a reference, the interference control unit selects to maintain the frame interval to be used at the short frame interval, and the busy situation The wireless communication apparatus according to claim 5, wherein when the reference is reached, the error characteristic is then confirmed. The long frame interval is initially set as the frame interval to be used,
The interference determination unit determines the error characteristic and the busy situation under the long frame interval,
The interference control unit selects to change the frequency channel when the error characteristic reaches a reference, and when the busy situation does not reach the reference, the interference control unit shortens the frame interval to be used. The radio communication apparatus according to claim 1, wherein the radio communication apparatus selects to change to a frame interval, and otherwise selects to maintain the frame interval to be used at the long frame interval.   The interference determination unit first determines the busy situation, and when the busy situation does not reach a reference, selects to change the frame interval to be used to the short frame interval, and the busy situation is a reference The wireless communication apparatus according to claim 7, wherein the error characteristic is confirmed next when the error rate is reached.   9. The criterion according to any one of claims 2 to 8, wherein the criterion for the error characteristic is that a reception error in the frame occurs continuously over at least a predetermined number of frames. Wireless communication device.   The interference determination unit has a function of managing a timer or is connectable to a function of managing a timer, and measures at least one of the error characteristic and the busy situation within a certain period until a timer timeout. The wireless communication device according to claim 1, wherein the wireless communication device is a wireless communication device.   The radio communication apparatus according to claim 10, wherein when the frame interval is changed to the short frame interval, a timer value of a timer to be started next is set longer than an original timer value.   Whether the interference control unit performs the change of the frequency channel in consideration of channel characteristics for each frequency channel prior to the change of the frequency channel when the change of the frequency channel is selected. The wireless communication apparatus according to claim 1, wherein a final determination is made as to whether or not.   The interference control unit makes the final determination based on the transmission rate in the current frequency channel and the time ratio in which the current frequency channel is free, the transmission rate in the change destination frequency channel, and the change destination frequency channel. The wireless communication apparatus according to claim 12, wherein the wireless communication apparatus is based on a relationship between a certain time ratio.   The interference control unit grasps in advance a time ratio in which the change-destination frequency channel is free, or regards a time ratio in which the change-destination frequency channel is free as a specific value. The wireless communication apparatus according to claim 13.   If the interference control unit does not select the change of the frequency channel and there is an error in transmission / reception of the frame, the transmission unit performs a fragment process to reduce the transmission data size and transmits the frame. The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus is selected to be performed.   The interference control unit transmits a connection request signal during connection processing to select whether the short frame interval is initially set or the long frame interval is initially set as a frame interval to be used first after completion of the connection processing. The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus performs the transmission based on a rate at which transmission is possible. In an interference avoidance method for a wireless communication device using a specific wireless communication method,
The transmitter of the wireless communication apparatus uses a frequency channel selected from a plurality of frequency channels, uses a frequency channel that can interfere with the specific wireless communication method, and is wider than the specific wireless communication method. Transmitting a frame at a short frame interval or a long frame interval compared to a predetermined frame interval used in another wireless communication system having a range; and
The reception unit of the wireless communication device receives the frame using the selected frequency channel; and
An interference determination unit of the wireless communication apparatus determines at least one of an error characteristic in the received frame and a busy state of the frequency channel being used;
The interference control unit of the wireless communication device changes the frequency channel, changes the length of the frame interval based on at least one of the error characteristic and the busy situation, or changes both And a method for controlling interference.

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